Elevator control



Oct. 2, 1962 Filed Nov. 10, 1959 L%J [Oct l-Om TERMINAL FLOOR |2TH FLOOR IITH FLOOR c. K. WILSON 3,056,469

ELEVATOR CONTROL 3 Sheets-Sheet l FROM OFI TERMINAL INVENTOR. CHESTER K. WILSON ATTORNEYS Oct. 2, 1962 c. K. WILSON 3,056,469

ELEVATOR CONTROL Filed Nov. 10, 1959 5 Sheets-Sheet s A AUXU &. 5% -4| 14c 55,42

AUXD me E -47 no 37, 4a

INVENTOR. CHESTER K. WILSON ATTORNEYS United States Patent Oflice 3,056,469 Patented Oct. 2, 1962 3,856,469 ELEVATOR CONTROL Chester K. Wilson, Cleveland, Ohio, assignor to Toledo Scale Corporation, Toledo, Ohio, a corporation of Ohio Filed Nov. 10, 1959, Ser. No. 851,983 27 Claims. (Cl. 18729) This invention relates to elevator systems in general and more particularly to controls for elevators. This invention also relates to a novel variable voltage regulator which may be utilized in conjunction with elevator controls as Well as elsewhere.

It is an object of this invention to improve elevator systems, to improve elevator service, and to increase the efiiciency and speed of response of elevators.

It is another object of this invention to provide an improved voltage regulator.

It is still another object of this invention to provide an improved voltage regulator which automatically adjusts the applied voltage on a generator shunt field so that the generator will generate the exact voltage an elevator motor requires to run an elevator car at a constant rate of speed, regardless of the load on the elevator.

It is a further object of this invention to provide an improved signal selector mechanism for an elevator system which functions in direct synchronism With the speed and the travel of the elevator cars.

It is a further object of this invention to improve the performance of elevator systems in the short run area, particularly floor to floor speed and runs of distances wherein the elevator car cannot reach full speed through the heretofore utilized means of acceleration.

In accordance with the above objects, the invention includes a novel voltage regulator which automatically adjusts the applied voltage on the generator shunt field. In a preferred embodiment the voltage regulator comprises a hydro-mechanical arrangement which includes a first cylinder and piston arrangement with a rod secured to the piston. The rod is connected to a sliding cam or a contact plate which cooperates with a rheostat to add or remove resistance from the shunt field of a generator. In a preferred form the rheostat may have a plurality of contacts which are elfective to accelerate the elevator car a predetermined number of feet per second, per second when the first piston moves relative to the first cylinder causing the sliding cam to cooperate with the contacts to successively cut resistance out of the shunt field. The first cylinder is connected to a fluid reservoir by a conduit having a three-way valve and a constant volume pump disposed therein. The constant volume pump as shown hereinafter is to be driven by a motor which is actuated at the same time as the main elevator motor. The constant volume pump is effective to draw fluid from the reservoir and inject it into the first cylinder operatively moving the piston and thus accelerating the elevator motor to its rated capacity through the cooperation of the piston movement and the cam operated rheostat.

in the elevator system a speed governor is utilized which includes a second cylinder and a second piston having a rod secured thereto. The upper end of the second rod has a predetermined weight attached thereto and, in the form shown hereinafter, a yoke which has secured to one arm a pair of racks and to the other arm a pair of cams. The first cam on the speed governor is eflective to weaken the motor shunt field by the operation of associated contacts. The first contact may be set to open at a predetermined number of feet per minute, e.g., 500 feet per minute. The racks cooperate with a selectively engageable pinion gear to drive a first sprocket on a selector machine mechanism through the agency of a chain operatively connected to said pinion gear which selectively engages one of the pair of racks.

The second cylinder is connected to a fluid conduit leading from the first cylinder. A variable volume pump is disposed in this conduit. The variable volume pump has the same displacement as the constant volume pump but is driven by the main elevator motor. When the main elevator motor and the constant volume and variable volume pumps have been started, fluid will flow from the reservoir to the first cylinder raising the first piston and, as the elevator motor starts to turn due to the accelerating current operatively received because of the rise of the first piston, the variable volume pump starts pumping a volume of hydraulic fluid directly in proportion to the speed of the main elevator motor. That is, the volume of fluid raising the first piston is the difference between the volume pumped by the constant volume pump and that pumped by the variable volume pump. The fluid pumped by the variable volume pump causes the second piston to rise in the second cylinder thereby operating the racks and switches associated with the cams responsive to the rise of the second piston. The net volume in the second cylinder is proportional to the speed of the elevator motor and thus also to the speed of the car. The speed at which the second piston raises may be determined primarily by the weight attached to the rod of said second piston and secondarily by a number of orifices in the side of the second cylinder.

The signal selector mechanism includes a first set of sprockets operatively connected by a first chain, a second set of sprockets operatively connected by a second chain, a guide, and a signal contact arm movable along the guide by means of a guide sprocket which is operatively engaged by the first and second chains of the signal selector mechanism. One of the second set of sprockets is operatively connected to the main elevator motor and thus the second chain will be driven in direct proportion to the travel of the car. One of the first set of sprockets is, as explained hereinbetore, operatively connected to the pinion gear driven by one of the pair of racks. Thus, the first chain connecting the first set of sprockets will advance the signal contact arm in direct proportion to the total travel of the speed governor which is governed by the speed of the car and which includes the second piston and cylinder equipment associated therewith. The second chain connecting the second set of sprockets will advance the signal contact arm in direct proportion to the travel of the car in the hatchway.

In previous applications for elevator controls there have been many attempts to provide means for greater floor to floor or short run speeds of an elevator car. These attempts have usually utilized a completely separate set of circuits for one floor or short runs or a completely separate mechanism or circuit in an attempt to solve the problem. Although the speeds of short runs have been a problem in the past it is expected to be an even greater problem in the future with the exploitation of basement floors for uses other than storage and maintenance. For example, many of the buildings being built today are designed with basement floors for parking areas either for tenants of the building or the customers of the tenants of the building. Since much of the service of this type would be initially from a basement floor to a first floor or lobby of the building the use of short run service of the elevator system would be intensified. Without means to increase the speed of the floor to floor or short runs of an elevator system, it might be necessary to install an additional number of cars to take care of the extended service requirements. The use of separate circuits or second separate mechanisms for short floor runs is more expensive and provides more maintenance and breakdown problems. Other attempts at solving this problem are usually as expensive and sometimes not as efiicient as desired.

Thus, the novel voltage regulator of this invention is cooperatively combined with the speed governor and a signal selector mechanism to increase the floor to floor speed of an elevator system, yet allowing the same combination to function as an elevator driving and control means for the remainder of the system requirements without any further modifications.

Other objects, features, and advantages of this invention not specifically pointed out above will become apparent when the following description is taken in conjunction with the accompanying drawings:

FIG. I is a schematic layout of a preferred embodiment of the voltage regulator, speed governor, and signal selecting means; and

FIGS. II and III are schematic diagrams of control circuits to be utilized with the apparatus of FIG. I.

The following relay list is provided to facilitate the understanding of the across the line schematic diagrams and to expedite the reading of the diagrams.

These relays and all others illustrated are shown in across the line diagrams. Their contacts therefore are often located remote from the actuating coils. In order to illustrate the relationship and location of actuating coils and contacts, a marginal key has been employed with each circuit diagram whereby the circuits are divided into horizontal bands which are identified by line numbers in the right hand margin of the figure. Relay symbols are located in that margin to the right of the key numerals and in horizontal alignment with the relay actuating coil positions. Each contact actuated by a relay coil is designated to the right of the relay symbol by the numeral of its line location. Back contacts, those which are normally closed when the relay armature is dropped out and are opened when the actuating coil is energized, are underlined in the key to distinguish them from front contacts, those which are closed upon the coil being energized. Thus, for example, down generator field relay DF has its actuating coil located on line 26 of FIG. II and when energized closes its front contacts at lines 14, 18 and 23 of FIG. ll, respectively designated in the margin as 14, 18 and 23 and opens its back contacts at line 25 of FIG. II designated in the margin by 25. Each contact is also labeled with the symbol of its actuating means and is illustrated in the condition it assumes while its armature is dropped out so that the front contacts of the down generator field relay are shown open as in line 14 and is labeled DP while the similarly labeled back contact in line 25 is shown closed.

Referring to FIG. I there is shown a preferred embodiment of the invention utilizing a hydraulic system for controlling an elevator motor which comprises in general a reservoir T of hydraulic fluid, a hydraulic conduit system generally designated at HC which includes a constant volume pump P1 and a variable volume pump P2.

A conduit connects the reservoir T and the constant volume pump P1. A conduit 11 and a three-Way valve V1 connects the constant volume pump P1 to a cylinder C1. The conduits 10 and 11 are connected through a conduit 12 and the three-Way valve V1, a conduit 13 and a solenoid actuated valve V2, a conduit 14 and a check valve V3, and a conduit 15 and a car leveling motor-pump combination PL. The cylinder C1 and the conduit 11 are connected to a conduit bridge arrangement designated generally at 20. The conduit bridge arrangement 20 comprises conduits 21 and 22 connected in parallel between the conduit 11 and a conduit 30. The conduit 21 has disposed therein check valves V8 and V5. A conduit 22 has disposed therein check valves V6 and V7. The junction of the check valves V8 and V5 is connected to the junction of the check valves V6 and V7 by a conduit 23 in which is disposed a variable volume pump P2. The conduit 30 is connected to the cylinder C2. The cylinder C2 is connected to a return chamber 31 and a return conduit 32 through a plurality of orifices 33 formed in the sides of the cylinder C2 and communicating with the return chamber 31. The return conduit 32 is connected to the reservoir T.

A piston PT3 in the cylinder C1 has a rod 40 connected thereto bearing a yoke 41. The yoke 41 has attached to one arm a cam 42. The yoke 41 has attached to the other arm a cam 43 and a cam 44. The cams 42 and 43 are electrically conductive and are electrically connected as will be explained hereinafter. The cams 42 and 43 are operative to be physically connected to the plurality of contacts RR and RL disposed on the rheostat R1 by movement of the piston PT3 in the cylinder C1. The cam 44 operates to close cam actuated contacts SG6 and SG7 by the action of the cam 44 on the insulated cam followers W6 and W7.

A piston P174 has a rod 50 connected thereto with means for applying or attaching a weight W to the end of the rod. The rod 50 also has a yoke 51 connected thereto. One arm of the yoke 51 carries racks R2 and R3. The other arm of the yoke 51 carries cams $2 and 53. The movement of the piston PT4 upward in the cylinder C2 cooperates with the cam 52 and the contacts associated with the resistance 54 to operatively insert and remove portions of the resistance 54 in an elevator motor shunt field. The movement of the piston PT4 also actuates speed governor contacts 5G1, SG2, 8G3, 8G4 and SGL by the cooperation of the cam 53 and the cam followers which are associated with each of the respective contacts.

A throwover limit switch motor T0 is operative to selectively engage the pinion gear GE with the racks R2 and R3 in response to signals denoting the direction of the elevator car travel. The detailed circuit of the throwover limit motor switch TO will be explained hereinafter. The gear GE may be pivotally mounted on a shaft or fixedly mounted on a shaft which in turn is rotatably mounted in a bearing. Upon receipt of an up or down direction signal the motor TO moves one of the racks R2 and R3 into engagement with the pinion gear GB. The pinion GE is connected by a chain C5 to a sprocket S5 which is one of a first pair of sprockets S3 and S5 connected by a chain C4 on a floor selector mechanism. A second set of sprockets S2 and S4 for the selector mechanism are connected by a chain C3. A signal arm C is mounted in a guide GU with a sprocket S6 pivotally attached thereto. The sprocket S6 is engaged with the chains C3 and C4 and is operative to move the signal arm C up and down in the guide GU in response to movement of either or both of the chains C3 and C4. That is, the signal arm C, sprocket S6, and guide GU assembly is operative to translate the rotational movement of the chains C3 and C4 into differential reciprocal lateral movement depending on the speeds, directions, and intervals of rotation of the chains C3 and C4. The second set of sprockets S2 and S4 are operatively rotatably connected by a chain C6 to a sprocket S1 driven by the main elevator motor EM. As was explained hereinbefore the elevator motor EM is operatively adapted to drive the pump P2 such that the pump P2 pumps a volume of hydraulic fluid in direct proportion to the speed of rotation of the elevator motor.

Referring to FIGS. 11 and III there is shown a circuit diagram of a control system which is utilized in conjunction with the embodiment of the invention as illustrated in FIG. I.

As in the usual elevator control system a direct current elevator motor EM that is connected to the elevator hoisting mechanism has its armature 110, shown in line 20, connected through leads 111 and 112 to the armature 113 of a variable voltage direct current generator. The armatures 110 and 113 together with the leads 111 and 112 constitute a loop circuit that includes a coil 114 of an overload relay, arranged to shut down the system should an overload current occur, and generator series field windings 115 and 116 that are wound to be cumulative compound with respect to a shunt field 126 of the generator. The loop circuit also includes normally open contacts M of a motor relay M in series with the normally open contacts H of a high speed relay H at line 21. The motor relay contacts M are bypassed with a resistor 117 so that the circuit is never completely open and the high speed contacts H and series field 116 are bypassed with a resistor 118. During standby operation, the opening of the motor relay contacts M inserts the resistor 117 into the loop circuit to reduce the circulating current through this circuit. The resistor 117 is shorted out of the circuit as soon as the motor is called upon to perform any work. The resistance of the loop circuit is also increased during low speed operation by the opening of the contacts H in line 21 to disconnect the high speed series field 116 leaving the shunt resistance 118 in the loop circuit. The series field 115 is adjusted in cooperation with the bypass resistor 119 and normally closed series field contacts SF to provide the proper compounding for low speed operation. The series field 116 is adjusted by varying the number of turns included in the circuit to secure proper compounding for high speed motor operation.

Shunt field excitation for the DC. motor is provided by current flow from a power supply lead L1 through the resistance 121, the coil of a field protection relay FP, the shunt field winding 123 of the elevator motor, all in line 11, and a cam operated rheostat 124 to a return power supply lead L2. The resistor 121 is included in the circuit to reduce the field current during standby operation, as when the car is standing at a floor. For normal excitation of the field which is required for normal or high speed operation, the resistor 121 is shorted out by contacts BK in line 12 of a brake relay BK that is energized when the brake is released and the motor is called upon to take the car away from the floor. Thus, the motor shunt field 123 is at least partially excited at all times that the system is in operation. The variable voltage generator has a shunt field 126, in line 17, that, for up operation of the car, is energized from the leads L1 and L2 by way of a circuit that may be traced from the lead L1, at line 14, through normally open contacts M of the motor relay M and contacts BK of the brake relay BK, up field relay contacts UF in line 18, a lead 127, the shunt field 126, lead 128, a second set of up field contacts UF, in line 14, and a rheostat R1 to the return lead L2. For operation in the opposite direction the up field relay contacts UF are opened and the down field relay contacts DF in lines 14 and 18 are closed to reverse the connections to the generator shunt field 126 at leads 127 and 128.

The excitation of the generator shunt field 126 is controlled primarily by the amount of resistance of the series resistors of the rheostat R1 that are included in series with the field winding.

' Referring again to FIG. I it may be seen that when the elevator system issues a signal for a car to start from a floor and the elevator motor EM and the motor M1 driving the constant volume pump P1 are simultaneously actu' ated the following sequence of operation results. The pump P1 draws hydraulic fluid from the reservoir T and 6 injects it through the three-way valve V1 into the cylinder C1 causing the piston PT3 to rise. As the piston PT3 rises the cam 43 makes contact with the first of the series of contacts RR on the rheostat R1 which is connected in a series circuit with the generator shunt field 126. The cam 42 makes contact with the ground contacts RL1, RL2, RL3 and RL4 which are connected through a ground lead including the first, second, and third slowdown limit switches 251 251 and 252, and the stop limit switch 253, to the return lead L2 through circuits which will be explained hereinafter. Since the cams 43 and 42 are electrically conductive and are also electrically connected together, the contact of the cam 43 with successive contacts RR of the RL series is operative to remove resistance from the generator shunt field circuit. That is, as the cams 42 and 43 are caused to rise by the action of the hydraulic fluid against the piston PT3 and thus the rod 40 connected to the piston, the cam 43 will successively contact the RR contacts of the rheostat R1 to remove resistance as hereinbefore discussed. A sutficient number of the RL series of grounding contacts are needed spaced in a relationship such that the cam 42 is always in contact with one of the RL series of contacts as it rises. That is, before the cam 42 loses contact with the lowermost grounding contact RL1 the upper portion of the cam 42 will have come into contact with the second grounding contact RL2. The successive removal of resistance from the elevator shunt field circuit causes the elevator motor EM to be accelerated at a predetermined number of feet per second, per second.

As the elevator motor receives accelerating current and starts to move it will cause the pump P2 to pump hydraulic fluid in direct proportion to the amount of rotation of the elevator motor EM and thus also directly proportional to the distance traveled by an elevator car being hoisted or lowered by the elevator motor EM. When the pump P2 starts pumping hydraulic fluid the piston PT4 is raised in the cylinder C2. As discussed hereinbefore the speed at which the piston PT4 raises may be governed primarily by the weight W attached to the rod 50 which is secured to the piston PT4 and secondarily by the number and size of orifices 33 in the side of the cylinder C2. When the elevator motor EM is rotating at such a speed so that the pump P2 is pumping the same amount of hydraulic fluid as the pump P1 the piston PT3 will stop rising in the cylinder C1 and the rated running speed of the elevator motor EM will have been reached.

This speed will be maintained automatically by the system as shown herein. For example, if the elevator motor begins to overspeed, as when a loaded car is descending, the pump P2 will be overdriven and will draw more hydraulic fluid than the constant volume pump P1 can supply. Consequently, fluid will be drawn from the cylinder C1 and the piston PT3 will begin to fall thereby putting resistance back into the generator shunt field circuit which slows down the elevator motor EM. If the elevator begins to overspeed, pump P2 discharges more fluid raising piston PT4 in the cylinder C2 thereby also advancing the signal arm C in direct proportion. Thus, if the elevator overspeeds and receives a stop signal before the voltage regulator reacts, the signal arm C will have been advanced enough beyond its ordinary position to receive the stop signal far enough ahead of time so that the slow down distance is greater and the ordinary stopping sequences will be elfective.

Assume that the elevator car had received a signal to answer a call in the up direction. An auxiliary up relay AUXU (not shown) is energized closing its contacts in lines 25 and 41. The auxiliary down relay AUXD (not shown) but having contacts in lines 26 and 42 is the analog of the AUXU relay for down operation. The closure of contacts AUXU at line 41 readies the call indicating circuits represented fragmentarily in lines 40 to 48. The closure of contacts AUXU in line 25 energizes the up generator field relay UF in line 25 and the brake relay BK in line 27. The energization of the AUXU relay is dependent upon the completion of any previous actions of the leveling circuits. That is, the AUXU relay cannot be energized if a car is in the leveling zone but not leveled, or if the leveling operation is still active. Although not shown the AUXU and AUXD relays may be dropped out by the inclusion of auxiliary leveling relay contacts LA, said LA relay to be described herein after, in their respective energizing circuits. The energization of the up generator field relay UF icloses its front contacts in lines 14 and 18 to energize the generator shunt field 126 as hereinbefore described, closes front cont-ancts UF in line 22 to energize the limit relay L, and opens back contacts in line 26 to exclude the possibility of the down generator field relay DF being energized. Brake relay contacts BK in line 13 close to release the brake, close in line 14 to allow energization of the generator field, and close in line 26 to seal in the energization of the up generator field, and brake relay circuits around the cam actuated RP contacts. The energization of the limit relay L causes its front contacts L in line 24 to close energizing the three-way valve relay V1 and causes back contacts L in line 29 to open deactivating the leveling circuits in lines 27 to 30 as the car moves away from the floor.

The direction throwover limit motor T at line 52 is energized to move the rack R2 into engagement with the pinion gear GE. If an up call is received the UP button or contact in line 50 is closed. A circuit is established through the TOU contact on the limit motor TO which energizes a winding of the TO motor through the back contacts BK of the brake relay BK at line 52 which is operative to shift the rack R2 into engagement with the gear GE. When the motor rotates for a desired interval the rack R2 is in engagement with the gear GE and the movement of the motor is operative to mechanically open the contacts TOU and stop the rotation of the motor while at the same time closing the contacts TOD in preparation for a down signal which would cause the rack R3 to be shifted into engagement with the gear GE. Thus, as the car moves away from the floor the piston PT4 rises causing the rack R2 also to rise thereby rotating the gear GB. The rotation of the gear GE will cause the first set of sprockets S3 and S5 to rotate because of the rotation of the chain C5 connected between the sprocket S5 and the sprocket S7 attached to the gear GE. Thus, the chain C4 connected to the sprockets S3 and S5 will rotate in a clockwise direction. At the same time the chain C3 will be driven in a counterclockwise direction by the sprockets S2 and S4, the sprocket S4 bein operatively connected to rotate in proportion to the rotation of the elevator motor EM by the connection of a chain C6 between a sprocket S1 driven by the elevator motor EM and the sprocket S4.

Assuming that the call is for the 11th floor and the elevator is on the first floor, the signal arm C will be advanced to the 11th floor stopping contact by the rotation of the chain C3 and the chain C4. Since the chain C4 rotated only while the piston PT4 was rising in the cylinder C2 and the rated speed was being attained, the major portion of the travel of the signal arm C was accomplished by the rotation of the chain C3 which is engaged with the sprocket S6 operatively attached to the signal arm C which is movably mounted in the guide GU. The lifting of the signal arm C by the lifting of the piston PT4 operates to advance the signal arm C a predetermined distance ahead of the actual travel of the car in the hatchway as represented by the rotation of the chain C3 which rotates in proportion to the distance the car travels in the hatchway when driven by the elevator motor EM. Thus, the signal arm C will arrive at the 11th floor sensing position or stopping contact a predetermined distance ahead of the time the elevator car in the hatchway actually physically reaches the 11th floor landing.

As was assumed hercinbefore a call was indicated for the car at the 11th floor. To accomplish this a landing button for the 11th floor at line 46 or a car push button at line 47 could have been closed to energize the 11th floor call relay 11C. When the relay 11C is energized it is sealed in by the closure of contacts 11C in line 48. The energization of the landing floor relay 11C closed its contacts 11C in line 37. Thus, when the signal arm C arrived at the stopping contact for the 11th floor in line 31, a stopping or call indication relay SS in line 33 is energized through the closed contacts BK of the brake relay in line 33, the closed contacts 11C of the car call relay 11C at line 37, and through a cam actuated switch SGl at line 36. The energization of the stop indication relay SS opens its back contacts at line 23 to deenergize the limit relay L, opens its back contacts at line 24 to deenergize the operating coil of the three-way valve V1, and closes front contacts in line 33 to seal in the stopping relay SS through contacts SS.

The deenergization of the operating coil of the valve V1 at line 21 causes the valve V1 to be switched so that the constant volume pump P1 can circulate fluid in the conduits 10, 11 and 12 while the motor M1 driving the pump P1 is slowing down and stopping, thus not damaging the pump P1 by suddenly closing a valve in its circulating path and not atlecting the accuracy of the system. Since pump P2 is no longer being supplied with fluid by the action of the pump P1 the pump P2 continues to pump hydraulic fluid from the cylinder C1 causing the piston PTS to be lowered in the cylinder C1. As the piston PT3 is lowered in the cylinder C1 it successively opens contacts RR and the RL series of the rheostat R1 and successively inserts resistance into the generator shunt field circuit thereby tending to slow the elevator motor EM down as the car moves in toward the floor. This operation continues until the piston PT3 is in its original position at the lower portion of the cylinder C1 and the energization has been removed from the elevator motor EM causing the pump P2 to stop pumping.

As the pump P2 was removing the hydraulic fluid from the cylinder C1 and thus causing the elevator motor to slow down thereby slowing the pumping action of the pump P2, the piston PT4 begins to descend in the cylinder C2 because of the slower pumping action of the pump P2. The weight W and the size and number of the orifices 33 in the Wall of the cylinder C2 determines the rate at which the piston PT4 lowers in the cylinder C2. When the hydraulic fluid is completely removed from the cylinder C2 through the orifices 33, the piston PT4 is resting again in its original position.

To insure that the signal arm C of the floor selector mechanism remains on the contact where it picked up a signal to stop a governor valve V4 may be disposed in the conduit 30 just before the speed governor piston and cylinder. The governor valve V4 is electrically operated and is responsive to the stop signal as shown in line 58 by the closure of stop indication contacts SS, that also causes the three-way valve V1 to stop the pumping of hydraulic fluid to the cylinder C1. The purpose of the governor valve V4 is to divert the fluid that is being pumped out of the cylinnder C1 after the car has received a stop signal by the pump P2 directly back to the reservoir T through a conduit 16. Thus, the fluid from cylinder C1 does not pass through the speed governor cylinder C2 and the rate at which the piston PT4 falls and the time at which the piston arrives at home or the bottom of the cylinder C2 can be further controlled to keep the signal arm C on the desired contact. The valve V4 is shown in FIG. I as a three-way valve but other types may be utilized to perform the intended function.

When the piston PT3 is home again in its original position, the cam operated switch RP in line 24 which is operated by the lower portion of the cam 44 is closed readying the brake circuit and the up generator field and down generator field circuit for operation when the car starts again. To level the elevator car at the floor the motorpump combination PL shown in FIG. I is operative to move fluid through conduit is from the conduit to the conduit 11. The motor-pump combination PL is operative to move a constant volume of hydraulic fluid through the conduit however at only a fraction of the volume of the fluid moved by the pump P1. The position of the car in the hatchway with respect to the landing to which it is being leveled is determined by leveling relays HLU and HLD (notshown) which are energized by the physical position of the car in the hatchway by magnetic detecting vanes. Such a detecting system for the physical position of the car in the hatchway is explained in greater detail in United States Patent No. 2,746,566, filed August 31, 1953, by E. B. Thurston.

Assume that the car is below the floor. The HLU contact in line 29 will then be closed energizing the up leveling relay LU in line 29. Therefore, the LU contacts in line 27 will be closed establishing a circuit through the up generator field relay UP and the closed down generator field contacts DF in line and through the brake relay BK in line 27 keeping the brake relay BK energized thus preventing the brake from being set before the car is leveled. The LU contacts in line 57 will be closed energizing the field PL of the motor-pump combination PL through the brake contact BK and the cam actuated contacts SL which are closed by the cam 42 and which are set to open at a predetermined speed, for example, twenty-five feet per minute. The motorpump combination PL will then draw hydraulic fluid from the reservoir T through the conduit 10, the conduit 15 and will cause the piston PT3 to rise a short distance. The rise of the piston PT3 on the cylinder C1 moves the car in the manner as hereinbe-fore explained until the vane in the hatchway which actuates the leveling relay HLU is no longer disposed to keep the HLU contacts at line 29 closed. The opening of the HLU contacts in line 29 deenergizes the leveling relay LU opening the contacts LU in line 27 allowing the brake to set, closing back contacts LU in line 28 to ready the down generator field circuit in case the leveling operation has overshot the floor and requires leveling in the down direction, and opens contacts LU in line 57 to deenergize the motor-pump combination PL. Since only a simple elevator system is being shown in order to level in the down direction and keep the signal arm C stationary the Down push button in line 54 must be closed to engage the rack R3 with gear GE. After leveling is accomplished and the car is ready to proceed up again then the UP push button in line 50 must be closed.

The opening of the gate causes deenergization of a gate relay G (not shown) which, in turn, will cause the opening of the front contacts G in line 24 deenergizing the brake relay BK and thereby allowing the brakes to set if the brakes have not already been set by other circuits. The opening of the landing floor doors will also open a switch 260 located in line 24 deenergizing the brake relay BK allowing the BK contacts in line 13 to open thereby causing the brake to set.

When leveling, the closure of the leveling relay contacts HLU and HLD in lines 29 and 30 is also operative to energize the auxiliary leveling relay LA in line 23. The energization of the auxiliary leveling relay LA opens its back contacts LA in line 23, opens back contacts LA in line 24, and closes front contacts LA in line 32. Thus, the limit relay L in line 23 is deenergized if it has not already been deenergized by the opening of the stop indication relay contacts SS in line 23. Similarly, the opening of the back contacts LA in line 24 insures the deenergization of the coil operating three-way valve V1. The closing of the front contacts LA in line 32 energizes the low series field switch relay SF which causes its back contacts in line 22 to open. The opening of the back contacts SF in line 22 removes the shunting resistance 119 from around the low speed series field 115 16 of the loop circuit. Thus, the motor EM is properly compounded for the low speed leveling operation.

Since only a simple elevator system is being illustrated, the car is set to travel up answering all calls on its way up until it reaches the top floor. Upon reaching the top floor the auxiliary up relay AUXU (not shown) is energized causing auxiliary up back contacts AUXU in line 41 to open so that all of the call indication relays may be reset and their respective contacts as represented fragmentarily in lines 41 through 48 will be opened. The up generator field relay UP is deenergized by the opening of AUXU contacts in line 25. Upon reaching the top floor, a top floor limit switch 271 in line 51 may be activated causing the rack shifting motor TO to rotate to bring into engagement with the gear GE the rack R3. Manual activation by the push buttons shown in lines 50 and 54 for up and down travel as indicated may also be utilized. It is to be realized that a number of means may be utilized to shift the racks R2 and R3 into respective engagement with the gear GE. When the car is to be set for down travel the auxiliary down relay AUXD (not shown) is energized closing its contacts in lines 26 and 42. The car is then ready to be operated in a down direction.

A number of safety features are incorporated in the invention. For example, if the belt, chain, gear or other connection between the elevator EM and the pump P2 breaks or becomes ineffective, speed governor switches SG2 and SGS at lines 19 and 23 are provided to prevent the elevator from being accelerated to too great a speed. The earn actuated speed governor contact 5G3 is disposed between the last rheostat grounding contact RL4 and the rheostat ground contact RL3. The cam actuated speed governor contact SG2 is disposed between the ground contacts RL3 and RLZ The speed governor contacts 863 and SG2 are actuated by a cam 53 attached to the yoke 51 as best seen in FIG. I which is moved up and down by the speed governor piston PT4. A speed governor contact 864 is also provided in line in the circuit for actuating the high series field switch relay H. A further speed governor contact SGl is provided in line 36 which operates to energize the landing call contacts represented fragmentarily in lines 34 to 57 after the car has reached a specified speed.

Assume that the connection between the elevator motor EM and the pump P2 is broken. The elevator motor and the motor M1 driving the constant volume pump P1 receives signals to start. The pump P1 starts pumping hydraulic fluid into the cylinder C1 causing the piston PT3 to rise. Since the pump P2 is not turning the piston PT3 will rise to the top of its travel limit in a very short time. If it were not for the speed governor contacts SG2 and SG3 this would remove all of the resistance of the rheostat R1 from the generator shunt field circuit and would accelerate the elevator motor and thus the car at its top speed. Again, since the pump P2 is not pumping the speed governor piston PT4 does not rise in the cylinder C2 and thus will not give an advance indication through the signal arm C that the car is approaching a floor at which a car call or landing call exists. Further, the cam 53 could not be rising since the piston PT4 is not rising so the speed governor switches SG2 and SG3 are still in an open position. Therefore, when the cams 42, 43 associated with the piston PT3 rise to their uppermost posi tion, the earns 42, 43 are operative to short out or remove resistance from the rheostat R1 in the generator shunt field circuit only for those contacts directly touching the cam 43 since the speed governor switches SG2 and 8G3 open the circuit to ground that is normally maintained through the right hand RL series of grounding contacts.

Although not shown in the drawings since it is well known in the art the pumps P1 and P2 may have relief valves that are operative to allow the conduction of the hydraulic fluid from the pumps back to the reservoir T if, because of any failures in the system, the pumps become overloaded to a predetermined pressure. This prevents the pumps from being damaged. As a further safety factor in the system an orifice OF 1 may be formed in the upper portion of cylinder C1 having a conduit OP connecting the orifice P1 with the reservoir T. In the interests of simplicity the conduit OP is shown only fragmentarily in FIG. I. The orifice would be positioned in the wall of the cylinder C1 so that the orifice would be above or covered by the piston PT3 when the cam 43 is contacting the last of the contacts RR of the rheostat R1. If the piston PT3 is pushed higher in the cylinder C1 because of the pumping action of the pump P1, when one or more of the check valves V8, V5, V6 and V7 or the pump P2 or other part of the system is inoperative, the hydraulic fluid has a safety outlet through the orifice 0P1 through the conduit OP back to the reservoir T.

The check valve V3 in the conduit 14 bypases the constant volume pump P1 connecting the conduits Jltl and 11 allows the system to be used on inspection runs. That is, inspection circuits are generally included with an elevator system in which means for furnishing predetermined excitation to the generator shunt field are available besides the rheostat R1 in the generator shunt field circuit as shown in the preset schematic drawings. Therefore, the elevator motor EM will rotate lowering or raising the elevator car as the inspector so desires and the check valve V3 allows the withdrawal of hydraulic fluid from the reservoir T without the energization of the constant volume pump P1. Thus, the operation of the elevator car is responsive only to the inspection circuits and is not responsive to any accelerating current as provided by the rheostat R1 since the running of the pump P2 and the operation of the valve V3 does not cause the piston PT3 to rise in the cylinder C1.

A further safety measure shown in the F168. II and III is the use of the acceleration responsive cam actuated contacts SG6 and S67 at lines 23 and 28 which are normally opened and are actuated closed by the cam 44 of FIG. I attached to the rod 40 which is secured to the piston PT3. The cam M is thus responsive to the movement of the piston PT3 and also responsive to the acceleration or excitation supplied to the elevator motor EM. As the piston PT3 rises in the cylinder C1 the cam actuated contact SG6 is closed first shorting a portion of the rheostat that is already shorted by the cooperating earns 42 and 43. As the cam E4 rises further the contact SG7 is closed, again shorting a portion of the rheostat R1 that is already shorted by the cooperating cams 42, 43. The cam 44 is of sufiicient length to keep the contacts SG6 and SG7 closed even though the piston PT3 and thus the rod 40 has reached its upward limit of travel. As will be noted in FIGS. II and III, first slowdown, second slowdown, third slowdown, and stop limit switches 250, 2551, 252 and 253 at lines 22, 27, 3t) and 37, respectively, are provided in series in the grounding circuit which is utilized by the grounding contacts RL1 through RL4- of the rheostat R1. The contact SG7, when closed, connects the rheostat R1 to a point in the grounding circuit intermed-iate the first slowdown and second slowdown switches, 259 and -1. The contacts SG6, when closed, connect a further point of the rheostat to a point in the grounding circuit intermediate the second slowdown and the third slowdown switches 251 and 252. It is well known in the art to utilize the slowdown and stop limit switches to stop a car as it approaches either limit of up or down travel in the hatchway and has not stopped as normally provided because of failure of other circuits. It is not deemed necessary here to show the actuating devices in the hatchway which open the respective slowdown switches and the stop limits as the car approaches the limits of hatchway travel.

Assume that there was a failure in the control system and the elevator car did not slow down to a stop at a terminal landing as it is supposed to do. Without the slowdown protection switches SG6 and C67, the hatchway actuated opening of the first slowdown switch would open the entire grounding circuit and suddently place the entire resistance of the rheostat R1 into the generator shunt field circuit causing the elevator car to stop suddenly, perhaps dangerously, and certainly uncomfortably. The SG6 and SG7 contacts are therefore utilized to connect the rheostat R1 to ground at points intermediate the slowdown switches so that as each slowdown switch successively opens only a predetermined portion of resistance is reinserted into the generator shunt field circuit. Therefore, the car slows gradually and safely in such an emergency case.

The above slowdown protection will also take care of the case when the piston PT3 might become stuck at the top of the cylinder C1 instead of normally descending as hereinbefore described. The entire rheostat R1 except for that portion shorted by cam 43 would again be removed from the generator shunt field circuit by the opening of the first slow down switch 250 if the switches SG6 and 567 were not included.

A further feature includes the operation of the high speed series field switch relay H at line 4-9 by a cam actuated contact SG4 which is responsive to a cam on the speed governor apparatus. The contact SG4 may be actuated as shown in FIG. I by the cam 53 and be set to close when the elevator motor has been accelerated to a predetermined speed, e.g., of full speed as measured by the speed governor apparatus. The high series field switch relay H is then energized closing its front contacts H in line 21 of the motor generator loop circuit so that the high speed series field 116 is included in the motor generator loop circuit and the motor is properly compounded to deliver high lifting and lowering speeds to the elevator car.

An additional means for raising the speed of the elevator motor EM and thus the speed of the car is the use of the cam 52 on the speed governor to actuate contacts 124 controlling the amount of resistance that the rhesostat 54 is inserting in series with the elevator motor shunt field 123. That is, when the elevator motor EM reaches a predetermined speed the cam 52 rises with the piston PT4 and cooperates with the contacts and rheostat 124 to operatively insert resistance in the elevator motor shunt field circuit thus allowing the motor to operate at a higher speed.

The speed governor switch SG1 in line 36 is normally open and may be set to close at a predetermined speed after the car has left the floor by the proper disposition of the cam actuated contact SG1 with respect to the cam 53 attached to the speed governor apparatus in FIG. I. When the switch SG1 closes the stopping circuit is readied so that when the signal arm C picks up the next stopping signal as denoted by a closed contact in the representative stopping circuits shown in lines 34 to 32 the car will receive the proper stopping signals and proceed with the sequences hereinbefore described.

A speed governor leveling switch SGL in line 29 is normally closed when the car is at a landing. A the car starts away from the landing the speed governor leveling switch SGL is opened by the cam actuation of cam 53 removing the leveling circuits represented by the contact shown in lines 26 to 31 from the possibility of nergization at a floor other than a floor at which a hall call or car call is registered.

In line 55 of FIG. III there is shown a simple circuit for energizing the reset valve V2. The reset valve V2 as illustrated in FIG. I is operative to connect the conduits 10 and 11 through conduit 13 which bypasses the constant volume pump P1. If a problem arises, such as discussed hereinbefore when the piston PT3 is stuck in the top or some place in the cylinder C1, or if the elevator car for any reason is stopped between floors, then the push button in line 55 may be closed energizing and opening the valve V2 so that the hydraulic fluid in the cylinder C1 may drain back through the conduit 13 to the reservoir T. This synchronizes the accelerating cams of the variable voltage regulator and the actual physical speed of the car as it is stopped in the hatchway. The piston PT4 would descend as the hydraulic fluid drains from the cylinder C2 through the orifices 33 and thus the signal arm C on the computer floor selector mechanism would be lowered or raised to a position on the floor selector corresponding to the actual physical position of the car in the hatchway.

The disposition of the check valves V8, V5, V6 and V7 in the two parallel conduits 21 and 22 allows the use of a hydraulic system which only has to pump in one direction and thus does away with more complicated pumping mechanisms that would be required if the direction of pumping had to be changed when the direction of car travel changed. That is, when the pump P2 i pumping hydraulic fluid up through the conduit 23 fluid flows from the conduit 11 through the check valve V6 and the check valve V to the conduit 30. If the direction of the elevator motor is reversed and the pump P2 pumps hydraulic fluid down through the conduit 23 as illustrated in FIG. I, hydraulic fluid flows through the conduit 11 through the check valve V8 and the check valve V7 to the conduit 30.

The slow down distance of the car can be changed by adding to or removing from the total weight W located on top of the speed governor. To change the rate of slow down the pitch diameter on the sheaves furnishing the drives to the pumps P1 and P2. may be changed provided that the pumps must be capable of passing the same volume of hydraulic fluid.

Thus, there is presented a system in which the speed and the actual travel of an elevator car are utilized to compute the slowdown distance that a stopping signal is picked up ahead of a floor at which a car or hall call is registered. Also disclosed is a novel variable voltage regulator which, although it may be utilized in other fields, is applied to an elevator system to automatically adjust the applied voltage on a generator shunt field so that the generator will generate the exact voltage that the elevator motor requires to run the elevator at a constant rate of speed regardless of the load on the elevator.

In summary, there is shown an elevator control which utilizes the following elements. An elevator car serving a plurality of floors is driven by an elevator motor. In the embodiment shown a variable voltage generator is electrically connected to the elevator motor for driving the motor. The generator has a control field having connected thereto an adustable rheostat to control the flow of current in the control field. It is to be noted that the variable voltage generator and the motor shown are only illustrative of driving means for the elevator car and means for controlling the speed of the driving means and thus the elevator car.

A hydraulic system is shown which is operatively connected to adjust the adjustable rheostat for the variable voltage generator or for adjusting other controls which may be utilized to vary the speed of an elevator driving motor. The hydraulic system includes means for circulating hydraulic fluid through the hydraulic system which are shown in the embodiment as including a constant volume pump and a variable volume pump. In the hydraulic system intermediate the constant volume and variable volume pumps there is shown a piston and cylinder arrangement which are movable with respect to each other. The variable volume pump pumps a volume of hydraulic fluid through the system which is proportional to the speed of the elevator motor. Thus, the connection of a piston and cylinder arrangement intermediate the constant volume and variable volume pumps constitutes a means responsive to a volume of fluid flow in the hydraulic system which is proportional to the diflerence between a predetermined desired speed and the actual speed of the elevator car. That is, the constant volume pump represents a flow of fluid which is proportional to the desired speed that the elevator car is to move and, as described herein, the variable volume pump moves a volume of fluid proportional to the speed of the elevator motor and thus also proportional to the speed of the elevator car. Therefore, the volume of fluid that flows into the piston and cylinder arrangement is proportional to and a measure of the diflerence between the desired and actual speeds of the car.

The piston and cylinder arrangement also represents a means responsive to pressure in the hydraulic system intermediate the constant volume and variable volume pumps. The hydraulic system as shown and disclosed also represents a hydraulic diflerential in which the output of the hydraulic differential is the movement of the piston with respect to the cylinder, said piston and cylinder arrangement being intermediate the constant volume and variable volume pumps. The output of this hydraulic differential is proportional to the diflerence between a predetermined desired speed and the actual speed of the elevator car. The embodiment thus shows apparatus for determining the difference in speed of the elevator car between a desired and an actual speed which is utilized to adjust the speed of the driving means and thus adjust the speed of the car.

In combination with the above discussed means, there is shown in the embodiment a novel floor selecting means. The floor selector means as shown comprises a fixed array of contacts and means for moving a signal contact or brsuh past this fixed array of contacts. The means for moving the signal contact or brush past the array comprises means responsive to the actual travel of the elevator car and means responsive to the speed of the elevator car. The mechanical means shown as means responsive to the travel of said car also represents means for generating a signal proportional to the travel of said car. That is, the second set of sprockets S2 and S4 and the connecting chain C5 to the elevator drive motor EM represents means for mechanically generating a signal proportional to the travel of the car. This is meant to include any electrical or electronic systems which simulate the travel of the elevator car and thus generate a signal proportional to the travel of the car. As disclosed in FIG. I the means responsive to the speed of the elevator car also represents means for generating a signal proportional to the velocity of the car. That is, the speed governor, the racks, the pinion gear, the connecting chain C5, and the first set of sprockets S3 and S5, represent means for mechanically generating a signal proportional to the velocity of the car. As above, this is meant to include any electrical or electronic means for generating a signal proportional to the velocity of the car. The floor selector means also includes means responsive to the generated travel and velocity signals adapted to provide a stopping signal for the elevator car. The sprocket S6 fulfills this function as being responsive to the movement of the chains of the first and second sets of sprockets and when the signal contact or brush arm C as moved up and down in the guide GU by the sprocket S6 arrives at a floor having a car or hall call the signal derived from the energized contact at the floor as simulated by the array of contacts provides a signal to stop the elevator car.

Since there are means shown for generating a signal proportional to the velocity of said car it can be said that the same means represents apparatus for generating a signal proportional to a derivative of car motion with respect to time. One such derivative of motion with respect to time is, of course, velocity or speed. Although not shown in the embodiment it is to be realized that acceleration, also a derivative of motion with respect to time (being a derivative of velocity) can be utilized in conjunction with car travel to build a floor selector means that operates according to the teachings of the invention shown and described herein. It is to be particularly noted that electronic apparatus may be utilized to generate the signals described hereinbefore and to provide an electronic dual of the mechanical apparatus shown herein.

Quite apart from the novel combination of the elevator system there is shown a hydraulic system for controlling a motor which is useful in other applications as Well. This hydraulic system comprises a reservoir of hydraulic fluid, adjustable means operatively connected to control the speed of the motor, means for circulating a fluid through the hydraulic system including a constant volume pump and a variable volume pump, said variable volume pump circulating an amount of fluid proportional to the speed of said motor, and means responsive to the pressure in said hydraulic system intermediate the constant volume and variable volume pumps which is adapted to adjust the adjustable means and thus the speed of the motor. The pressure responsive means, of course, comprises the piston and cylinder arrangement controlling the movement of the cam which cooperates with the rheostat and the plurality of switches as described hereinbefore. In addition, for the motor control the piston and cylinder arrangement is responsive to the volume of fluid flow between the constant volume pump and variable volume pumps.

The elevator relays and contacts shown herein are not meant to be an all inclusive, refined approach to a new philosophy or mode of operation a group or bank of elevators but rather are utilized to exemplify the novel motor control, floor selector means operation, and other inventive aspects taught herein.

In conclusion it is pointed out that while the illustrated example constitutes a specific embodiment of my invention, I do not limit myself to the exact details shown, since modification of the same may be made without departing from the spirit of this invention.

Having described the invention, I claim:

1. In an elevator control, in combination; an elevator car that serves a plurality of floors; elevator driving means; adjustable means operatively connected to control the speed of said driving means; hydraulic system means operatively connected to adjust said adjustable means including means responsive to a volume of fluid flow in said hydraulic system Which is proportional to the difference between a predetermined desired speed and the actual speed of said elevator car; floor selector means for said car comprising means for generating a signal proportional to the travel of said car, means for generating a signal proportional to the velocity of said car, and means responsive to said travel and velocity signals adapted to provide a stopping signal for said elevator car.

2. In an elevator control, in combination; an elevator car that serves a plurality of floors; elevator driving means; adjustable means operatively connected to control the speed of said driving means; hydraulic system means operatively connected to adjust said adjustable means including means responsive to a volume of fluid flow in said hydraulic system which is proportional to the difference between a predetermined desired speed and the actual speed of said elevator car; floor selector means for said car comprising means for generating a signal proportional to the travel of said car, means for generating a signal proportional to a derivative of car motion with respect to time, and means responsive to said travel and derivative signals adapted to provide a stopping signal for said elevator car.

3. In an elevator control, in combination; an elevator car that serves a plurality of floors; elevator driving means; adjustable means operatively connected to control the speed of said driving means; hydraulic system means operatively connected to adjust said adjustable means including means responsive to a volume of fluid flow in said hydraulic system which is proportional to the difference between a predetermined desired speed and the actual speed of said elevator car; floor selecting means for said i6 car comprising an array of fixed contacts, and means for moving a signal contact past said array.

4. In an elevator control, in combination; an elevator car that serves a plurality of floors; elevator driving means; adjustable means operatively connected to control the speed of said driving means; hydraulic system means operatively connected to adjust said adjustable means including means responsive to a volume of fluid flow in said hydraulic system which is proportional to the difference between a predetermined desired speed and the actual speed of said elevator car; floor selecting means for said car comprising an array of fixed contacts, and means for moving a signal contact past said array; said signal contact moving means including means responsive to the speed of said elevator car and means responsive to the travel of said elevator car.

5. In an elevator control, in combination; an elevator car that serves a plurality of floors; elevator driving means; adjustable means operatively connected to control the speed of said driving means; hydraulic system means operatively connected to adjust said adjustable means including means responsive to a volume of fluid flow in said hydraulic system which is proportional to the diiference between a predetermined desired speed and the actual speed of said elevator car; tloor selecting means for said car comprising an array of fixed contacts, and means for moving a signal contact past said array.

6. In an elevator control, in combination; an elevator car that serves a plurality of floors; elevator driving means; adjustable means operatively connected to control the speed of said driving means; hydraulic system means operatively connected to adjust said adjustable means including means responsive to a volume of fluid flow in said hydraulic system which is proportional to the difference between a predetermined desired speed and the actual speed of said elevator car; floor selecting means for said car comprising an array of fixed contacts, and means for moving a signal contact past said array; said signal contact moving means including means responsive to the speed of said driving means and means responsive to the number of revolutions of said driving means.

7. In an elevator control, in combination; an elevator car that serves a plurality of floors; an elevator driving means; adjustable means operatively connected to control the speed of said driving means; a hydraulic system; means for circulating fluid through said hydraulic system including a constant volume pump and a variable volume pump; said variable volume pump circulating an amount of fluid proportional to the speed of said driving means; means responsive to pressure in said hydraulic system intermediate said constant volume and said variable volume pumps operatively connected to adjust said adjustable means.

8. In an elevator control, in combination; an elevator car that serves a plurality of floors; an elevator driving means; adjustable means operatively connected to control the speed of said driving means; a hydraulic system; means for circulating fluid through said hydraulic system including a constant volume pump and a variable volume pump; said variable volume pump circulating an amount of fluid proportional to the speed of said driving means; means responsive to pressure in said hydraulic system intermediate said constant volume and said variable volume pumps operatively connected to adjust said adjustable means; floor selector means for said car comprising means for generating a signal proportional to car travel, means for generating a signal proprotional to the velocity of said car, and means responsive to said travel and velocity signals adapted to provide a stopping signal for said car.

9. In an elevator control, in combination; an elevator car that serves a plurality of floors; an elevator driving means; adjustable means operatively connected to control the speed of said driving means; a hydraulic system; means for circulating fluid through said hydraulic system including a constant volume pump and a variable volume pump; said variable volume pump circulating an amount of fluid proportional to the speed of said driving means; means responsive to pressure in said hydraulic system intermediate said constant volume and said variable volume pumps operatively connected to adjust said adjustable means; floor selecting means for said car comprising an array of fixed contacts, and means for moving a signal contact past said array of fixed contacts; said signal contact moving means including means responsive to the speed of said car and means responsive to the travel of said car.

10. In an elevator control, in combination; an elevator car that serves a plurality of floors; an elevator driving means; adjustable means operatively connected to control the speed of said driving means; a hydraulic system; means for circulating fluid through said hydraulic system including a constant volume pump and a variable volume pump; said variable volume pump circulating an amount of fluid proportional to the speed of said driving means; means responsive to pressure in said hydraulic system intermediate said constant volume and said variable volume pumps operatively connected to adjust said adjustable means; floor selecting means for said car comprising an array of fixed contacts, and means for moving a signal contact past said array; said signal contact moving means including means responsive to the travel of said car and means responsive to the volume of fluid pumped by said variable volume pump.

11. In an elevator control, in combination; an elevator car that serves a plurality of floors; elevator driving means; adjustable means operatively connected to control the speed of said driving means; differential means having an output operatively connected to adjust said adjustable means; said output of said differential means being proportional to the difference between a predetermined desired speed and the actual speed of said elevator car; floor selector means for said car comprising means for generating a signal proportional to the travel of said car, means for generating a signal proportional to the speed of said car, and means responsive to said travel and speed signals adapted to provide a stopping signal for said elevator car.

12. In an elevator control, in combination; an elevator car that serves a plurality of floors; elevator driving means; adjustable means operatively connected to control the speed of said driving means; differential means having an output operatively connected to adjust said adjustable means; said output of said differential means being proportional to the dilference between a predetermined desired speed and the actual speed of said elevator car; floor selector means for said car comprising means for generating a signal proportional to the travel of said car, means for generating a signal proportional to a derivative of car motion with respect to time, and means responsive to said travel and derivative signals adapted to provide a stopping signal for said elevator car.

13. In an elevator control, in combination; an elevator car that serves a plurality of floors; elevator driving means; adjustable means operatively connected to control the speed of said driving means; differential means having an output operatively connected to adjust said adjustable means; said output of said differential means being proportional to the difference between a predetermined desired speed and the actual speed of said elevator car; floor selecting means for said car comprising an array of fixed contacts, and means for moving a signal contact past said array of fixed contacts; said signal contact moving means including means responsive to the speed of said car and means responsive to the travel of said car.

14. In an elevator control, in combination; an elevator car that serves a plurality of floors; an electric elevator drive motor; a variable voltage generator electrically connected to the motor for driving said motor; said generator having a control field; an adjustable rheostat connected to control the flow of current in the control field;

a hydraulic system; means for circulating hydraulic fluid through said system including a constant volume pump and a variable volume pump; said variable volume pump being responsive to the speed of said motor; means operatively connected to adjust said rheostat in response to the pressure in said hydraulic system intermediate said constant volume and said variable volume pumps.

15. In an elevator control, in combination; an elevator car that serves a plurality of floors; an electric elevator drive motor; a variable voltage generator electrically connected to the motor for driving said motor; said generator having a control field; an adjustable rheostat connected to control the flow of current in the control field; a hydraulic system; means for circulating hydraulic fluid through said system including a constant volume pump and a variable volume pump; said variable volume pump being responsive to the speed of said motor; means operatively connected to adjust said rheostat in response to the pressure in said hydraulic system intermediate said constant volume and said variable volume pumps; floor selector means for said car comprising means for generating a signal proportional to the travel of said car, means for generating a signal proportional to the velocity of said car, and means responsive to said travel and velocity signals adapted to provide a stopping signal for said elevator car 16. In an elevator control, in combination; an elevator car that serves a plurality of floors; an electric elevator drive motor; a variable voltage generator electrically connected to the motor for driving said motor; said generator having a control field, an adjustable rheostat connected to control the flow of current in the control field; a hydraulic system; means for circulating hydraulic fluid through said system including a constant volume pump and a variable volume pump; said variable volume pump being responsive to the speed of said motor; means operatively connected to adjust said rheostat in response to the pressure in said hydraulic system intermediate said constant volume and said variable volume pumps; floor selecting means for said car comprising an array of fixed contacts, and means for moving a signal contact past said array; said signal contact moving means including means responsive to the travel of said car and means responsive to the volume of fluid pumped by said variable volume pump 17. In an elevator control, in combination; an elevator car that serves a plurality of floors; an electric elevator drive motor; a variable voltage generator electrically connected to the motor for driving said motor; said generator having a control field, an adjustable rheostat connected to control the flow of current in the control field; a hydraulic system; means for circulating hydraulic fluid through said system including a constant volume pump and a variable volume pump; said variable volume pump being responsive to the speed of said motor; means op= eratively connected to adjust said rheostat in response to the pressure in said hydraulic system intermediate said constant volume and said variable volume pumps; floor selecting means for said car comprising an array of fixed contacts, and means for moving a signal contact past said array of fixed contacts; said signal contact moving means including means responsive to the speed of said car and means responsive to the travel of said car.

18. In a hydraulic system for controlling a motor, in combination; a reservoir of hydraulic fluid; adjustable means operatively connected to control the speed of said motor; means for circulating said hydraulic fluid through said hydraulic system including a constant volume pump and a variable volume pump; said variable volume pump circulating an amount of fluid proportional to the speed of said motor; means responsive to the pressure in said hydraulic system, intermediate said constant volume and said variable volume pumps, operatively connected to adjust said adjustable means.

19. In a hydraulic system for controlling a motor, in

combination; a reservoir of hydraulic fluid; adjustable means operatively connected to control the speed of said motor; means for circulating said hydraulic fluid through said hydraulic system including a constant volume pump and a variable volume pump; said variable volume pump circulating an amount of fluid proportional to the speed of said motor; means responsive to the pressure in said hydraulic system, intermediate said constant volume and said variable volume pumps, operatively connected to adjust said adjustable means; said pressure responsive means comprising a piston and cylinder arrangement movable with respect to each other and controlling the movement of a cam.

20. In a hydraulic system for controlling a motor, in combination; a reservoir of hydraulic fluid; adjustable means operatively connected to control the speed of said motor; means for circulating said hydraulic fluid through said hydraulic system including a constant volume pump and a variable volume pump; said variable volume pump circulating an amount of fluid proportional to the speed of said motor; means responsive to the pressure in said hydraulic system, intermediate said constant volume and said variable volume pumps, operatively connected to adjust said adjustable means; said pressure responsive means comprising a piston and cylinder arrangement movable with respect to each other and controlling the movement of a cam, and a rheostat having a plurality of switches; said cam being adapted to actuate said switches to control the total value of resistance of said rheostat.

21. In a hydraulic system for controlling a motor, in combination; a reservoir of hydraulic fluid; means for circulating said hydraulic fluid through a hydraulic system including a constant volume pump and a variable volume pump; said variable volume pump circulating an amount of fluid in proportion to the speed of said motor being controlled; means responsive to the pressure in said hydraulic system between said constant volume and said variable volume pumps; said pressure responsive means being operatively connected to regulate the speed of said motor in response to said pressure.

22. In a motor control system, in combination; a variable voltage generator electrically connected to a motor for driving said motor; said generator having a control field; an adjustable rheostat connected to control the flow of current in the control field; a hydraulic system; means for circulating fluid through said hydraulic system including a constant volume pump and a variable volume pump; said variable volume pump being responsive to the speed of said motor; means responsive to the pressure in said hydraulic system, intermediate said constant vol- 2Q ume and said variable volume pumps, operatively connected to adjust said rheostat.

23. In an elevator control, in combination; an elevator car that serves a plurality of floors; elevator driving means; adjustable means operatively connected to control the speed of said driving means; hydraulic system means operatively connected to adjust said adjustable means including means providing a volume of fluid flow in said hydraulic system which is proportional to the ditference between a predetermined desired speed and the actual speed of said car, and means responsive to said volume of fluid flow in said hydraulic system.

24. In an elevator control, in combination; an elevator car that serves a plurality of floors; elevator driving means; adjustable means operatively connected to control the speed of said driving means; hydraulic system means operatively connected to adjust said adjustable means including means providing a volume of fluid flow in said hydraulic system which is proportional to the difference between a predetermined desired speed and the actual speed of said driving means, and means responsive to said volume of fluid flow.

25. Floor selecting means for controlling an elevator car that serves a plurality of floors, comprising; means for generating a signal proportional to the travel of said car, means for generating a signal proportional to the velocity of said car, and means responsive to said travel and velocity signals adapted to provide a stopping signal for said elevator car.

26. A commutating device for commutating an array of electrodes in a system to correlate the operation of said system with respect to a traveling element thereof comprising means for advancing the efiective location of said commutating device with respect to said array in accordance with the current advancement of the position of said traveling element along its path of travel and means for further advancing the effective position of said commutating device on said array as a function of a derivative of traveling element motion with respect to time.

27. Floor selector means for an elevator car that serves a plurality of floors comprising an array of electrodes, means for commutating said electrodes, means to advance the effective position of the commutating means on said array in accordance with the then current advancement of the position of the elevator car with respect to said floors and means for further advancing the location of the commutating means on said array as a function of the current speed of said car.

No references cited. 

